Figured out my problem anyways and probably the problem of the OP. When you click on someones name and then choose send private message it takes you to their user page and pops up a send message box. In this box it fills in the send to name with their actual name. For instance I was trying to PM TIm White of wetsounds and it kept filling in "TIm White" in the send to box instead of his username "wetsounds1". This is no doubt an error on the site's part.